To meet a variety of requirements such as broadband services, service quality, and network coverage, the 3GPP launches a completely new evolved network, namely, an evolved packet system (EPS). Referring to FIG. 1, FIG. 1 is a network architecture diagram of the EPS. The EPS includes an evolved UMTS terrestrial radio access network (E-UTRAN), a mobility management entity (MME), a serving gateway (S-GW), a PDN gateway (Packet Data Network Gateway, P-GW), a serving GPRS support node (SGSN), a home subscriber server (HSS), and a policy and charging rules function (PCRF).
The E-UTRAN is used to implement all functions related to radio access in the evolve network. The MME is used to take charge of mobility management on a control plane, including user context management, mobility status management, allocation of a temporary user identity, and the like. The S-GW is a gateway terminated on an E-UTRAN interface, and is used as a user plane anchor between 3GPP access systems. The P-GW is a gateway that terminates a SGi interface towards a packet data network, and is used as a user plane anchor between a 3GPP access system and a non-3GPP access system. The PCRF is used to implement policy control decision and traffic-based charging functions. The HSS is used to store user subscription information. The SGSN is used to implement routing and forwarding, mobility management, session management, user information storage, and the like in a GPRS/UMTS network. In addition, a GSM/EDGE radio access network (GERAN) and a UMTS terrestrial radio access network (UTRAN) in FIG. 1 are used to implement all functions related to radio access in the GPRS/UMTS network.
During evolution of the GPRS network to the EPS, the SGSN evolves from supporting a Gn/Gp interface to supporting an S4 interface, and an interface between the SGSN and the HSS also evolves from a MAP-based Gr interface to an S6d interface supporting Diameter, where the SGSN supporting the Gn/Gp interface is called a Gn/Gp-SGSN. Considering that within a relatively long period, the SGSN in the EPS needs to support access of GPRS users to an EPS network by using the GERAN/UTRAN, the SGSN in the EPS needs to have functions of the Gn/Gp-SGSN in the GPRS network. The GPRS network provides a mechanism for implementing a CAMEL (Customized Applications for Mobile network Enhanced Logic) service, and the Gn/Gp-SGSN may selectively support a CAMEL function. Therefore, when the Gn/Gp-SGSN supports the CAMEL function, the SGSN in the EPS also needs to support the CAMEL function, that is, the SGSN needs to receive user subscription data that is sent by the HSS and includes CAMEL service data.
In a process of implementing the embodiments of the present disclosure, the inventor finds that the conventional art has the following technical problems: When the SGSN in the EPS supports a CAMEL function, because the S6d interface does not support transmission of CAMEL service data, the SGSN acquires all user subscription data from the HSS by using the MAP-based Gr interface. Acquisition of the user subscription data by using the MAP-based Gr interface causes the SGSN not to use the S6d interface, and some optimization procedures defined on the S6d interface for scenarios in which an SGSN and an MME are integrated cannot be implemented.